hns_roce_alloc_cmd_mailbox() never returns NULL, so the check should be
IS_ERR(). And the error code should be converted as the function's return
value.
Link: https://lore.kernel.org/r/20220302064830.61706-8-liangwenpeng@huawei.com
Signed-off-by: Wenpeng Liang <liangwenpeng@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
 
        /* Allocate mailbox memory */
        mailbox = hns_roce_alloc_cmd_mailbox(hr_dev);
-       if (IS_ERR_OR_NULL(mailbox))
-               return -ENOMEM;
+       if (IS_ERR(mailbox))
+               return PTR_ERR(mailbox);
 
        ret = alloc_eq_buf(hr_dev, eq);
        if (ret)
 
 
        /* Allocate mailbox memory */
        mailbox = hns_roce_alloc_cmd_mailbox(hr_dev);
-       if (IS_ERR(mailbox)) {
-               ret = PTR_ERR(mailbox);
-               return ret;
-       }
+       if (IS_ERR(mailbox))
+               return PTR_ERR(mailbox);
 
        if (mr->type != MR_TYPE_FRMR)
                ret = hr_dev->hw->write_mtpt(hr_dev, mailbox->buf, mr);
 
        }
 
        mailbox = hns_roce_alloc_cmd_mailbox(hr_dev);
-       if (IS_ERR_OR_NULL(mailbox)) {
+       if (IS_ERR(mailbox)) {
                ibdev_err(ibdev, "failed to alloc mailbox for SRQC.\n");
-               ret = -ENOMEM;
+               ret = PTR_ERR(mailbox);
                goto err_xa;
        }